Most common fish viral diseases

A: Field-level / Presumptive methods:

·       Case history and clinical signs

·       Postmortem lesions

·       Rapid test Kits (Antigen: KHV, SVCV, VNN)

·       Water quality parameters.

·       New trend ‘New Field-lab’

-  Portable qPCR: Run WOAH assay in 1 hr at hatchery.

-  Digital PCR:  quantification for carrier fish with very low load of virus.

-  eDNA qPCR: environmental DNA qPCR used to detect virus from pond water.  

B: Laboratory methods / Confirmatory methods

·       WOAH - World Organization for Animal Health – requires 2 lab methods for official confirmation of listed virus diseases. the laboratory methods include:

1-Virus Isolation in Cell Culture

2-Molecular Methods:                                                      

·     Conventional PCR

·     Real-time qPCR

·     LAMP - Loop-mediated isothermal amplification

·     Sequencing

3-Serological Methods:

·       Serum Neutralization.

·       IFAT - Indirect fluorescent antibody techniques.

4. Histopathology study

·       Histopathology

·       Immunohistochemistry IHC

5.   Fluorescence In-Situ Hybridization FISH

6. Electron Microscopy